1. Field of the Invention
This invention relates to an antenna angle adjusting mechanism for a wireless audio/video transmitter.
2. Description of the Prior Art
With regard to an antenna for transmitting and receiving high frequency signals, it is essential that the azimuth angle and the elevation angle of the antenna may be widely adjusted so as to reduce the blind comer for transmitting and receiving signals. FIG. 1 is an exploded perspective view showing the angle adjusting mechanism for an antenna 110 in a conventional wireless video and audio transmitter. In this case, the antenna 110, having a connecting sleeve 111, is connected to a casing 120 through a hollow tube 100 including three pivoting sleeves 101, 102 and 103 which form a generally T-shaped appearance. The pivoting sleeve 101 is connected to the antenna 110 through the connecting sleeve 111 which enables the antenna 110 to rotate around the axis of the pivoting sleeve 101 of the hollow tube 100 in order to adjust the azimuth angle of the antenna 110. The other two pivoting sleeves 102 and 103 are aligned to each other and are pivotably connected to the pivoting recess 121 of the casing 120, which enables the hollow tube 100 to pivot relative to the casing 120 around the axis of the two pivoting sleeves 102 and 103 so as to adjust the elevation angle of the antenna 110.
After the angle of the antenna 110 has been adjusted to a desired position, the antenna 110 must be retained at the same position so as to optimize its transmitting and receiving capability. To this end, when the above mentioned three pivoting sleeves 101, 102, and 103 of the hollow tube 100 are pivotably connected to the casing 120 and the antenna 110, an O ring 105 made of resilient material such as rubber must be interposed between the connected portions for generating a damping effect to maintain the antenna 110 at a desired position after angle adjustment.
One drawback of the above mentioned prior art is that each of the three pivoting sleeves of the hollow tube 100 requires to be assembled with an O ring 105, which causes an increased assembly costs due to increment in the time and material required for assembly.